The Tower of Joy scene certified Lyanna Stark and Rhaegar Targaryen as Jon’s true parents, meaning Jon isn’t merely a northern lord’s bastard—he’s the rightful heir to the Iron Throne.
But we basically knew all that, it was an unconfirmed-confirmed fact even before the finale aired. What we never knew- and still don’t know- is what Jon’s actual name is. We hear Lyanna whisper “his name is…” but we only see her say the name (damn you audio engineers!). A name that has three syllables. A name that cannot possibly be Jon, or Rhaegar for that matter.
Instead, Redditor sparkledavisjr posits Jon’s true name to be…Jaehaerys. Who’s Jaehaerys? Glad you asked:
“Jaehaerys I was the 4th Targaryen king to sit the Iron Throne. He was known as ‘the Wise,’ ‘the Conciliator,’ and ‘the Old King.’ His long rule was prosperous and he was aided by his sister-wife Alysanne, who convinced Jaehaerys to expand the Night’s Watch and granted them the land now known as the New Gift.
Jaehaerys II was Jon’s great-grandfather. His reign was short due to his ill-health (only three years), but still a good one. Jaehaerys restored stability to the realm, ended the Blackfyre threat during the war of the Ninepenny kings, and improved relations with the major houses who were unhappy during his father’s rule (Aegon V — Egg, the brother of Maester Aemon).
If Lyanna was in love with Rhaegar (as seems likely), it makes sense for their son to have a Targaryen traditional name like his siblings Aegon and Rhaenys. Jaehaerys would be a good pick as the name isn’t associated with any real negative connotations, like Aerys, Maegor, etc.”
“Sister-wife Alysanne,” looking at all you Jon/Sansa shippers out there.
He goes on to explain that Ned probably gave his nephew the pseudonym ‘Jon’ in honor of his own father figure- Jon Arryn. Makes sense. Definitely not as good as Trump’s ‘John Miller‘ alias, but certainly more symbolic.